Joshua bbown



(No Model.)

. 'J. BROWN.

KEY HOLE GUARD.

No. 269,824. Patented Jan. 2, 1883.

:UNITED STATES PATENT OFFICE.

JOSHUA BROWN, OF QUINCY, MASSACHUSETTS, ASSIGNOR OF ONE-HALF TO FREDERICK HARDWICK, OF SAME PLACE.

KEY-HOLESGUARD.

SPECIFICATION forming part of Letters Patent No. 269,824, dated January 2, 1883,

(No model.)

To all whom it may concern:

Be it known that I, JOSHUA BROWN, of Quincy, in the county of Norfolk and State of Massachusetts, have invented certain new and useful Improvements in Key-Hole Guards. of which the following is a specification.

Door-locks as heretofore constructed and now in general use and applied to outside doors when locked serve only as a slight protection against the entrance of thieves or burglars, on account of the ease and facility with which they may be unlocked from the outside by means of pliers adapted [0 enter the key-hole and turn the key left in the look upon the inside; and in case the key be removed therefrom, then the lock may be picked or unlocked by skeleton keys. These and other objections are o ercome by my invention, which consists in the construction, combination, and arrangement of a sliding plate upon one or both sides of the lock, adapted to be actuated by turning the key thereofin to the proper position for removal after thebolt is thrown or locked, which movement of the key actuates or slides a plate over the key-hole in the opposite side of the lock, thereby completely closing the key-hole against the introduction of a by or other device whatever, as hereinafter more fully described and set forth.

Figure 1 represents a perspective view of a door-lock, a portion being broken away to show the a1.)plication of my invention. Fig.2 shows a plan view of one plate or side of the lock, with sliding plate in position to be slid over the key-hole. Fig. 3 is a sectional view of the lock with sliding plates in position relative to the key, and showing the formation of the upper and lower or inward and outward edges or surfaces of the key, which cause the opposite plates to be moved over the key-hole.

A represents the case of the lock, of usual construction.

B B represent sliding key-hole guard-plates, being provided at one end with a small projection, O, and held in the proper position by one or more spiral or other friction-springs, D, which bear against the inner surface of the said sliding plates B, as shown in Fig. 3.

E represents the spindle of the key, having a bearing-seat against the outer surface of the casing Act the lock. ward end of said spindle E stops short or ends just before reaching the sliding plate B, so as to permit the straightfaced inward edge or lower end portion of the key-bit F to come in contact with the projection Goa the sliding The lower end or inplate B when the key-bit arrives at the position shown in Fig. 2 after locking the bolt.

It will be seen in Fig. 3 that the notch H in the upper or opposite edge portion of the key bit G permits this portion of the key-bit to pass the projection U of the sliding'plate B, and thus slide plate B over the key-hole without disturbing plate B, and the-reverse operation when the key is inserted in the opposite side of the look.

This kind of lock may be provided with one or more levers, as usual.

Having thus described my invention, What I claim isy The combination, with a door-lock, of the sliding plates B B, each provided with a projection, G, and held in position by the spiral friction-spring D, and a key-bit having the portions F and G, all being constructed .and arranged substantially asshown anddescribed, as and for the purposes set forth.

JOSHUA BROWN.

Witnesses:

FREDERICK HARDWIGK, J AS. E. TIRRELL. 

